Understanding Necrotizing Fasciitis: The Flesh-Eating Bacteria
Necrotizing fasciitis, commonly called “flesh-eating bacteria,” is a rare but severe bacterial soft tissue infection that can spread rapidly and cause extensive tissue damage. It is a catastrophic infection that can lead to amputation or death. If recognized early and treated successfully, necrotizing fasciitis will have a better outcome. It presents itself as a cellulitis case and confuses healthcare professionals. Necrotizing fasciitis can spread rapidly, and the condition of the patient can deteriorate even though the patient is in the hospital under the care of physicians. It may be too late by the time we figure it out; here’s what you need to know about this severe infection.
What is Necrotizing Fasciitis?
Necrotizing fasciitis is an infection that targets the body’s soft tissue, particularly the fascia, which is the connective tissue surrounding muscles, nerves, fat, and blood vessels. The bacteria responsible for this condition can enter the body through a break in the skin, such as cuts, burns, insect bites, or surgical wounds. The condition is diagnosed clinically by the appearance of skin discoloration, bullae, and crepitus. Two other diagnostic methods can support the diagnosis: calculation of the LRINEC score and frozen section from a biopsy. Treatment is aggressive debridement and broad-spectrum IV antibiotics. Differential diagnosis will inlude gas gangrene and cellulitis
Causes and Risk Factors
Necrotizing fasciitis, commonly known as flesh-eating, is a limb and a life-threatening soft tissue infection. The bacteria produce toxins and spread rapidly. There is also an association between hepatitis C and Necrotizing fasciitis. The most common cause of necrotizing fasciitis is an infection with polymicrobials, which is the most common (80-90%) — seen in immunosuppressed (diabetics and cancer patients).
Monomicrobial Group A β-hemolytic Streptococci is the most common organism isolated, present in 5% of cases. It is Seen in healthy patients’ extremities and rarely seen in Marine Vibrio (gram-negative rods).
Symptoms to Watch For
The symptoms of necrotizing fasciitis can be mistaken for other, less severe conditions initially, but it escalates rapidly and spreads quickly. Early signs include severe pain, soreness, and minimal swelling, similar to a “pulling” sensation at the injection site beyond what would be expected from the injury. Pain and Tenderness beyond the apparent margin of infection is diagnostic and found in 98% of cases.
Later, the patient may have other symptoms and findings, including:
- Red, Erythema 100% or purple skin in the affected area, Skin necrosis 14%
- Bullae formation of less than 50%
- Swelling and warmth in the affected area
- Fever 50% chills, and fatigue
- Tachycardia 75%
- Hypotension 18%
- Later stages might show blisters, black spots, ulcers, or pus on the skin.
- gas and crepitus 14%
Imaging is usually not necessary
Diagnosis and Treatment
Early diagnosis and treatment are critical for survival. Diagnosis typically involves a combination of physical examinations, blood tests, tissue biopsies, and rarely imaging. Once diagnosed, treatment usually involves intravenous antibiotics and emergency radical surgical debridement of all infected tissue — hyperbaric oxygen in anaerobic bacteria. Resuscitation and hemodynamic stability are also necessary. Surgical debridement should be urgent. Debridement should be repeated on an almost daily basis. A delay in surgery of more than 24 hours is associated with increased mortality. In severe cases, amputation of the affected limb may be required to stop the infection from spreading.
The best clinical diagnosis is by seeing skin discoloration, bullae, and crepitus. In addition to calculating the LRINEC score, more than 6 points have a positive predictive value of 92%. Calculating the values from the CRP of more than 150 will give 4 points, including white cell count, hemoglobin, sodium, creatinine, and glucose. Abnormal value will give 2 points. A very high CRP can be very diagnostic. A biopsy is done as an emergency, and a frozen section can confirm the diagnosis in the early stages; it can be done at the bedside with a small sample of one cm.
The LRINEC (Laboratory Risk Indicator for Necrotizing Fasciitis) scoring system is used to help diagnose necrotizing fasciitis, a severe skin infection. It assesses risk based on lab values like C-reactive protein and white cell count. While it aids in early detection and objective evaluation, it’s not foolproof and should complement, not replace clinical judgment. It’s effective for resource allocation and decision-making in healthcare settings but has limitations, including the potential for misdiagnosis and reliance solely on lab data. Despite its drawbacks, it’s valuable in managing suspected necrotizing fasciitis cases.
Biopsy
A biopsy is done as an emergency; a small incision can be made over the involved area in the clinic, the emergency room, or the OR, with direct inspection of the fascia and the muscles. This may differentiate between necrotizing fasciitis and cellulitis. A frozen section can confirm the diagnosis in the early stages; it can be done with a small sample of one cm. A culture is usually obtained to determine the species of bacteria present within the wound. The gram stain may show gram-positive cocci in chains (group A streptococci) or polymicrobial.
Patients may have less-than-satisfactory outcomes despite early diagnosis and adequate treatment. The two cases presented are examples of difficulties in diagnosis.
Prevention and Awareness
Preventing necrotizing fasciitis involves proper wound care, including cleaning all cuts and injuries, covering wounds, and monitoring for signs of infection. If an injury becomes red, swollen, or increasingly painful, spreading quickly, especially if you have a fever, immediate medical attention should be sought.
PROGNOSIS, with a mortality rate of 30 % mortality, correlates with time to surgical intervention; it is underdiagnosed initially because it resembles low-grade cellulitis.
There is a high incidence of extremity amputation if the fascia is penetrated by infection or if the treatment is delayed.
Conclusion
While necrotizing fasciitis is rare, its rapid progression and severe consequences highlight the importance of early detection and treatment. Understanding the symptoms and seeking prompt medical care can significantly improve outcomes for those affected by this devastating infection. Awareness and education are vital in preventing the spread of this potentially fatal condition.
